body{
    margin: 10px;
    padding: 10px;
}

.yig {
    width: 900px;
    height: 1500px;
    margin: 0 auto;
    padding: 8px;
}
.a1 {
    width: 100%;
    height: 100px;
    border-bottom: 8px solid slategray;
    background-color: red;
}
.b2 {
    height: 400px;
    width: 200px;
    background-color: seagreen;
    float: left;
}
.c3{
    width: 500px;
    height: 195px;
    float: left;
    background-color:yellow;
    border-bottom: 5px solid slategray;
}
.d4 {
    height: 400px;
    width: 200px;
    background-color: seagreen;
    float: right;
}
.aa {
    width: 164px;
    height: 200px;
    float: left;
    background-color: skyblue;
}
.bb {
    width: 160px;
    height: 200px;
    border-right: 5px solid red;
    border-left: 5px solid red;
    float: left;
    background-color: thistle;
}
.cc {
    width: 166px;
    height: 200px;
    float: left;
    background-color: yellowgreen;
}
.erge {
    width: 100%;
    height: 100px;
    border-top: 8px solid slategray;
    background-color: red;
    float: left;
}